Airline fleets today tend to be rather large, especially the U.S. airline fleets that may have hundreds of mainline aircraft. Anyways, I was wondering how much of these aircraft are used on like a daily, weekly or monthly basis, I say that cause I dont know if airlines park certain ships on certain frequencys... during the months, weeks, or daily on the individual aircraft schedule. Basically it seems that some airlines, Delta for example, might only need no more then 30 of their 767s a day to cover their 767 route system, then again I could be wrong. I do know (as we all do) that Delta has a massive fleet of like plus 70 767s, so what My main question is, are aircraft rotated and many of the fleet not used on a daily, weekly, or monthly basis? Maybe some airlines use all there fleets on say a daily basis (maybe 90+ percent), but use each incorperated aircraft just a small amount, then it again probably depends on the airline. Well I'm extreamly interested in this subject so I'm looking forward to hearing people's advice, info etc... Thanks a lot!
brian

On any given day maybe 5-8% of the aircraft are not being used by DL. Out of any given fleet type there are maybe two of each type in for Heavy Maint checks and 3-4 more down for shorter checks like a letter check or engine change. Most planes spend at least 10 hours in the air. Remember aircraft are an expensive asset that makes no money while sitting. The reason large airlines have so many planes is because they need them to fly the daily routes. right now many airlines, including DL have some aircraft parked in long term storage.

Dalmd88's post explains why some of the majors (US, DL, etc.) use 767s & 777s to Florida...the planes make no money while sitting & they can fill them up on those routes while they have some time before/after they head for Europe. Is this the reason why Delta's schedule ATL-MCO has nothing smaller than a 767-200 (except a weekend MD-88)?

Dalmd88's post explains why some of the majors (US, DL, etc.) use 767s & 777s to Florida...the planes make no money while sitting & they can fill them up on those routes while they have some time before/after they head for Europe.

I've never seen Delta use an -ER 763 on Florida flights and I have only rarely seen them on other domestic flights. The -ER's are the ONLY type used for international travel.

Is this the reason why Delta's schedule ATL-MCO has nothing smaller than a 767-200 (except a weekend MD-88)?

The Florida flights pretty much all have high load factors (It's less than an hour flying time from JAX-ATL and the last three 763's I've been on have been full). Remember, the route doesn't have to be long haul to need high capacity!